They aren't all prospects but they all could help you in one way or another. Here is one player from each team worth picking up for the 2nd half of the season. Note: All players are 30 percent owned or less in Yahoo! Sports Fantasy Baseball.
Arizona Diamondbacks - 3B Matt Davidson - The Futures Game MVP and AAA HR Derby winner will be bringing his bat to the desert very soon, hopefully before September.
Atlanta Braves - RP David Carpenter - If you're in a Roto league and need help lowering your ERA, then RPs can sure come in handy, like this guy!
Baltimore Orioles - OF/DH Henry Urrutia - The newest former Cuban Major Leaguer, he hit .367 in his short season in the minors, debuted at DH for the O's but can play the OF as well.
Boston Red Sox - SS Xander Bogaerts - His numbers slipped a bit after being promoted to AAA, but they've been coming back with a vengence (.297, 3 HR, 10 RBI last 10 games).
Chicago Cubs - OF Junior Lake - May be jumping the gun a bit, but a 3-hit debut plus a .295 average in AAA has to at least put him on your radar.
Chicago White Sox - SP Andre Rienzo - Though he sat out 50 games to serve a suspension, he's gotten back on track and put up a sub-2.5 ERA in his last 10 starts. The White Sox could trade Peavy at the deadline, opening up a spot for the MLB's first Brazilian player.
Cincinnati Reds - OF/SS Billy Hamilton - The best speedster in the minors and, though his average remains low, he'll swipe enough bags to warrant an addition to your team.
Colorado Rockies - 2B Charlie Culberson - Somebody that's better on your watch list, but he's been red hot in AAA this year, including a .409 average over his last 10 games
Detroit Tigers - 3B/OF Nick Castellanos - He's been a consistent hitter at all minor league levels and has the pop to make it in the majors (12 HR, 50 RBI so far in AAA).
Houston Astros - OF George Springer - This guy does everything: He hits, he runs and puts the ball over the fence. Expect him in Houston sooner rather than later
Kansas City Royals - OF David Lough - Hitting .291 since being called up, starting consistently for KC and, if he keeps his average there, for your team as well.
Los Angeles Angels - OF Kole Calhoun - Got a cup of coffee in the majors last year and has been demolishing it in AAA, hitting well over .400 in his last 10 games and should be demanding a call-up or trade to a less crowded OF core.
Los Angeles Dodgers - RP Chris Withrow - If Dodger closers continue to struggle, he could be given the next chance. No saves in the minors but boasts a strong 11.2 K/9 on the season between AAA and the majors.
Miami Marlins - OF Christian Yelich - I'm surprised he hasn't been brought up after the slew of prospects already at the major league level, hitting .271 throughout the minors this season and is a must-add in any keeper league once he gets the call.
Minnesota Twins - SP Kyle Gibson - After a solid few months in AAA, he's had some trouble with the Twins. Wait until he puts together solid starts back-to-back before jumping on him.
Milwaukee Brewers - SP Wily Peralta - He's put together a few great starts in a row and is getting the hang of being a regular in the rotation.
New York Mets - 1B Josh Satin - If (while) Ike Davis continues to struggle, Satin will continue to hit, and at a high rate with a .338 BA.
New York Yankees - SP Michael Pineda - After nearly two full seasons of injury, Pineda is back in the minors and ready for another shot at the big leagues.
Oakland Athletics - OF Michael Choice - Stuck around with the big club during spring training, showing he belongs there with great AAA numbers (.291 BA, 61 RBI).
Philadelphia Phillies - OF Darin Ruf - Hit .266 in AAA but has fared much better at the major league level (.333). Grab him up if any Philly OF gets injured.
Pittsburgh Pirates - SP Jamison Taillon - Hit a rough patch in July but is still a huge prospect. Should get a September call up.
San Diego Padres - 2B Dean Anna - Though not much of a prospect at 26, he's still hitting well enough (.331 BA, 8 HRs, 49 RBI) to get his first major league call up.
San Francisco Giants - 1B/OF Brett Pill - Had some trouble during his initial call-up but has been killing it in AAA (.343 BA, 73 RBI).
Seattle Mariners - SP Taijuan Walker - Only 2 ER in 4 AAA starts, Walker is surely an option after the Mariners move Joe Saunders after the trade deadline.
St. Louis Cardinals - OF Oscar Taveras - It's possible he's already taken if you're in a deep league, but he's one of the game's best hitting prospects and is expected in St. Louis this September.
Tampa Bay Rays - RP Alex Torres - This guy boasts a 0.34 ERA and 33 K's in 26.1 IP and though he doesn't get saves, he's sure to snipe a couple.
Texas Rangers - 2B/SS Jurickson Profar - Hasn't lived up to the hype this season but will be huge for any keeper league and could get into a groove over the stretch run of the season.
Toronto Blue Jays - RP Steve Delabar - Another great add if you're in Roto and behind in ERA: The All-Star has his at 1.88 with 59 K's in 43 IP.
Washington Nationals - SP Taylor Jordan - He killed it in the minors this year with a 1.00 ERA in 90.1 IP and, though his K numbers are low in the majors, so are his BBs.